Dialog-based voiceprint security for business transactions

ABSTRACT

A system for biometrically securing business transactions uses speech recognition and voiceprint authentication to biometrically secure a transaction from a variety of client devices in a variety of media. A voiceprint authentication server receives a request from a third party requester to authenticate a previously enrolled end user of a client device. A signature collection applet presents the user a randomly generated signature string, prompting the user to speak the string, and recording the user&#39;s as he speaks. After transmittal to the authentication server, the signature string is recognized using voice recognition software, and compared with a stored voiceprint, using voiceprint authentication software. An authentication result is reported to both user and requestor. Voiceprints are stored in a repository along with the associated user data. Enrollment is by way of a separate enrollment applet, wherein the end user provides user information and records a voiceprint, which is subsequently stored.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 60/312,363, filed Aug. 14, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates generally to the field of biometric authentication. More particularly, the invention relates to a system and method for securing business transactions using dialog-based voice recognition and voiceprint authentication.

[0004] 2. Description of Related Technology

[0005] The ability to positively and reliably authenticate an individual is of utmost importance in areas such as e-commerce and financial services provided in a networked environment. Conventional shared secret authentication technology involves numerous disadvantages that motivate a continuing search for more reliable authentication technologies. For example, passwords and PIN's (personal identification number), while easily implemented, are easily compromised. Often, workplaces having aggressive password policies requiring passwords to be changed frequently also discourage easily remembered passwords. Thus, the inconvenience of trying to remember a password is such that end-users often write their password down so that they won't forget it. It is extremely common to see a user's password displayed in their office in plain view, perhaps on a POST-IT note affixed to their desk. Furthermore, replacing the passwords of those who have forgotten theirs is a significant expense in many organizations. The same problems are encountered in e-commerce and financial service environments. Conventional authentication methods render it relatively simple for a party to masquerade as someone else, resulting in serious invasions of privacy, and often inflicting grave financial or reputational harm.

[0006] Biometric authentication, the use of unique physical characteristics to verify an individual's identity, is receiving an increasing amount of attention. The use of fingerprints to positively identify an individual has been known for several hundred years. T. Tabuki, Verification server for use in authentication on networks, U.S. Pat. No. 5,987,232 (Nov. 16, 1999) describes the use of signatures to authenticate users requesting network access. The user records his or her signature by means of an electronic signature tablet. The recorded signature is then verified on a verification server. R. Glass, M Salganicoff, U. Cahn von Seelen, Method and apparatus for securely transmitting and authenticating biometric data over a network, U.S. Pat. No. 6,332,193 (Dec. 18, 2001) describes use of a retinal scan to authenticate a user requesting network access. Y. Yu, S. Wong, M. Hoffberg, Web-based, biometric authentication system and method, U.S. Pat. No. 6,182,076 (Jan. 30, 2001) describes a biometric authentication architecture implemented as middleware that employs encryption and passwords to lessen the possibility that a user's biometric data will be compromised while being transmitted to an authentication center.

[0007] A disadvantage to most current biometric authentication technologies is that they are subject to compromise. A user's biometric data can be intercepted and misused in the same way that a password can. In order to minimize such possibility, as described in the references above, measures must be taken to make sure that the biometric data is securely transmitted, and is authentic, requiring measures such as encryption, watermarking and passwords. It would be advantageous to provide a simple, reliable way of minimizing the possibility that biometric data has been compromised, or is not authentic.

[0008] Another disadvantage of most biometric authentication schemes is that the biometric templates are stored independently of their associated user data. The biometric data received from a user desiring authentication is first matched with a template from the template database. Subsequently, the individual associated with the matching template is provided. While such methodology is well suited for biometric identification, it is resource intensive. It would be desirable to provide a way of granting direct access to particular user's biometric template without first matching the templates.

[0009] Biometric authentication schemes are often implemented as middleware in a network environment. It would be desirable to provide a server-based architecture wherein the server is optimized for biometric authentication.

[0010] A still further disadvantage to most biometric authentication schemes is that they require dedicated sensing devices, such as specialized cameras for retinal scans and digitizing tablets for signatures. Often these devices are difficult to implement and maintain, requiring special software drivers and frequent calibration and adjustment. Thus, it would be an advance to provide a means of biometric authentication that doesn't require specialized input devices

[0011] Use of biometric authentication has been limited to granting access, often to a data network. It would be desirable to provide security for business transactions over either voice or data networks based on biometric authentication.

SUMMARY OF THE INVENTION

[0012] A system for biometrically securing business transactions uses speech recognition and voiceprint authentication to biometrically secure a transaction from a variety of client devices in a variety of media. A voiceprint authentication server receives a request from a third party requestor, often a server running a business application, to authenticate a previously enrolled end user of a client device. In response, the authentication server instantiates a signature collection applet on the client device. Any client having audio recording capabilities, a software environment and memory capable of running the applet, readable configuration data that can serve as a device signature, and the ability to send the signature is suitable for the invention. During an interactive dialog, the signature collection presents the user a randomly generated signature string, prompting the user to speak the string, and recording the user's utterance as he speaks. The dialog-driven nature of the signature gathering process, coupled with the use of a randomly generated signature string, provides an important liveness check. While the invention is completely compatible with industry standards for secure transmission and digital signatures, the liveness check provides a high degree of security for the collected voice data independently of other security measures.

[0013] After being transmitted to the authentication server, the signature string is first recognized using voice recognition software, and the string subsequently compared with a stored voiceprint, using voiceprint authentication software. Based on the comparison, an authentication result is reported to the user and the requester. Voiceprints are stored in a repository along with the associated user data. The invention is capable of operating over one or both of a data network and a voice network.

[0014] Enrollment is by way of a separate dialog-based enrollment applet, wherein the end user provides user information and records a voiceprint, which is subsequently stored.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 provides a functional flow diagram of a system for biometrically securing business transactions using speech recognition and voiceprint authentication according to the invention;

[0016]FIG. 2 illustrates the architecture of a voiceprint authentication server according to the invention;

[0017] FIGS. 3A-F show a series of screen shots corresponding to the steps of an enrollment process according to the invention; and

[0018] FIGS. 4A-C show a series of screen shots corresponding to the steps of an authentication process according to the invention.

DETAILED DESCRIPTION

[0019] The invention provides a system and method that use voice recognition and voiceprint technologies to biometrically secure transactions from a variety of devices over a variety of media. The system, as described herein below, is compatible with industry standards for secure transmission, digital signatures, etc., and can be combined with other biometric and data security techniques to provide improved levels of security to a variety of transactions, for example electronic business transactions.

[0020] Referring now to FIG. 1, shown is a functional flow diagram of the invented system 100.

[0021] 1. Request for authentication:

[0022] Any business application 101, running on any server, can request authentication for any specific pre-enrolled user at any time. This may occur prior to transaction completion (e.g., checkout a shopping cart, trade stocks, transfer funds). The business application requests authentication by signaling the voiceprint server with an identifier for a specific user at a specific network address.

[0023] 2. Serve up signature collection applet.

[0024] A voiceprint server 102 instantiates a signature collection applet on a client device 103 at the network address provided by the business application. There are several varieties of the applet, depending upon the kind of end-user device (PC, Palm, telephone, etc.) and the software supporting the business transaction on that device (browser, client software, etc.). Any client having audio recording capabilities, a software environment and memory capable of running the applet, readable configuration data that can serve as a device signature, and the ability to send the signatures is suitable for the invention. FIGS. 4A-C provide screen shots of an exemplary user interface to the signature collection applet. As FIG. 4A shows, the signature collection applet alerts the user, giving the user the option to continue 401. Following the initial alert, the voiceprint server 102 randomly generates a signature string used to collect speech data by the signature collection applet.

[0025] 3. The applet collects a voice and data signature.

[0026] The signature collection applet (device- and software-specific) renders a dialog box on the client device displaying the randomly generated string 402, prompting the user to click the ‘record’ button 403, and speak the signature string 402 into the device microphone. The dialog box prompts the user to click a ‘stop’ button when finished recording 405 and then click a ‘submit’ button 404. (FIG. 4B). In the event that the user needs to repeat the process he starts over by clicking a ‘try again’ button 406.

[0027] In the case of a telephone device, the system calls the device and asks the end-user to speak the signature string.

[0028] The applet uses device-specific recording objects to record the speech as an audio file, for example a wav file, although other file formats are consistent with the spirit and scope of the invention. The applet also reads the device configuration data (e.g., Windows registry) to generate a device signature.

[0029] The user's signature audio file and device's configuration data are sent by the applet to the voiceprint server 102. While the data transfer and authentication processing is occurring, the applet displays a “processing” message (not shown) on the end-user device 103.

[0030] 4. The authentication server receives the audio file and device configuration from the applet.

[0031] The server passes the audio file, device configuration, and signature string to the speech recognition and voiceprint authentication software, and requests recognition with respect to the recorded signature string and verification with respect to the specific user's voiceprint (already on record, as described below).

[0032] The speech recognition software returns a recognition result that is compared against a configurable recognition confidence level; and the voiceprint authentication software returns a verification result that is compared against a configurable verification confidence level. If both confidence levels exceed established thresholds, the server determines that the user is authenticated. If the confidence levels of both results are below their minimum respective thresholds (also configurable), the user is rejected as an imposter. If one or both of the confidence levels are between the threshold values, the voiceprint server generates a new random signature string and retries the process. The number of retries is configurable.

[0033] When the server has made its determination, the authentication result is sent to the applet, as shown in FIG. 4C. The applet displays the result (“You have been authenticated” or “We were unable to authenticate your voice”) and then terminates. In addition, the voiceprint server sends the authentication result to the business application.

[0034] Referring now to FIG. 2, shown is a block diagram that illustrates the various server-side 200 components:

[0035] DISPATCHER (201). Sub-components within the dispatcher include:

[0036] A load balancer—receives authentication requests and directs them to available authentication clients 202;

[0037] A system logger—logs system load data for performance and data analysis; and

[0038] A watcher—starts and shuts down authentication clients in response to system demand, terminates unresponsive authentication clients, and restarts authentication clients that terminate abnormally.

[0039] AUTHENTICATION CLIENT (202). Sub-components within the authentication client include:

[0040] A transaction manager—receives authentication request from the business application 101, responds to progress queries from the business application, and returns the authentication result to the business application;

[0041] A logger—logs the authentication transaction data for performance and data analysis;

[0042] A random signature generator—generates the random signatures for use by the signature collection applets;

[0043] An applet launcher—using device configuration data and the network address, the applet launcher serves up the appropriate signature collection applet to the end user device and receives the signature files from the applet. It also sends the authentication result to the applet for display;

[0044] An authentication requester—passes the audio file to the voiceprint server along with the user id requesting recognition and verification results. Uses device signature, as appropriate, to identify best acoustic models for recognition and verification; and

[0045] A dialog manager—stuffs dialog box content into the applets. Evaluates recognition and verification results as compared to configured thresholds. Determines the authentication result and the potential need for retries. Interacts with other client components to manage the data and decision flow.

[0046] ENROLLMENT CLIENT (203). Sub-components within the enrollment client include:

[0047] An enrollment manager—receives enrollment request and device specific data from the user, manages the dialog with the user, and confirms the completion of the enrollment process;

[0048] A logger—logs the enrollment transaction data for performance and data analysis;

[0049] An identity manager—manages the user-specific data necessary to confirm the identity of the user during the enrollment process;

[0050] An applet launcher—using device configuration data and the network address, the applet launcher serves up the appropriate applet (enrollment, FIG. 3) to the end user device and receives the signature files from the applet. It also sends the enrollment result to the applet for display;

[0051] An enrollment requestor—passes the audio file to the voiceprint server along with the user identity information requesting recognition and verification results. Use device signature, as appropriate, to identify best acoustic models for recognition and verification; and

[0052] A dialog manager—stuffs dialog box content into the applets, evaluates recognition and verification results as compared to configured thresholds, determines the enrollment result and the potential need for retries, interacts with other client components to manage the data and decision flow. Stores the voiceprint in the repository.

[0053] AUTHENTICATION APPLET (FIG. 4)

[0054] Construction—there are many device-specific authentication applets, for PCs, Palms, Microsoft CE devices, WAP phones and other portable devices capable of recording speech. In addition, telephony servers such as Voice mail and IVR systems are supported with authentication applets to allow voiceprint security for messaging, IVR or even agent-handled voice transactions;

[0055] Instantiation—the applet is served up by the authentication client to run on the target device or has been pre-installed on the target device. It is provided a random signature and dialog content by the authentication client;

[0056] Dialog—presents the text to instruct the user to speak the specified digit string and present the results, additionally, handles any retries required;

[0057] Records the speech—using device specific resources (e.g., windows recorder) records the utterance and formats into an audio file;

[0058] Device configuration—Reads the device configuration information and prepares it for transmission to the authentication client for use as a device signature; and

[0059] Data transfer—transfers the audio file and device configuration to the authentication client.

[0060] VOICEPRINT SERVER (204)

[0061] Receives files—receives data from the authentication client for recognition and verification;

[0062] Software interface—integrates with speech recognition and verification API's to pass audio files and select appropriate grammars and acoustic models. Also receives recognition and verification results; and

[0063] Voiceprint manager—manages storage and retrieval of voiceprints from the data repository.

[0064] The invention further includes a number of API's (application program interfaces), among them:

[0065] AUTHENTICATION REQUEST API

[0066] The business application requests authentication, sending the following information to the authentication client:

[0067] User id;

[0068] Network address;

[0069] Device configuration (if known);

[0070] The authentication client responds with the authentication result as follows:

[0071] User id;

[0072] Authentication pass/fail, or one of various errors (e.g., invalid user ID)

[0073] APPLET API

[0074] The signature collection and enrollment applets instantiate on the end-user device 103 and use device specific resources as follows:

[0075] Audio recorder (windows media recorder, etc); and

[0076] Device configuration file.

[0077] VOICEPRINT SERVER API

[0078] The voiceprint server interacts with speech recognition and voiceprint verification software 206 using their API's 205. It sends the following data:

[0079] Recognition request with grammar name and audio file;

[0080] Verification request with user ID and audio file; and

[0081] Results with confidence scores returned to server.

[0082] Enrollment Applet

[0083] As described above, users must have previously enrolled their voiceprint on the system, prior to being able to be authenticated. FIGS. 3A - F depict the various stages of the enrollment process from the user perspective, showing dialog boxes as they are presented to the user. As FIG. 3A shows, the user first provides his Account ID 301 and password 302. As in FIG. 3B, the user is prompted to supply an enrollment number 303. As in FIGS. 3C - E the user then records his voiceprint, using controls corresponding to the user interface of the signature collection applet: ‘record’ 304, ‘stop’ 305, ‘try again’ 306 and ‘submit’ 307. Recording of the voiceprint includes the following steps, for each of which the user receives a prompt:

[0084] Record account ID (FIG. 3C);

[0085] Record the numbers 0-9 a first time (FIG. 3D); and

[0086] Record the numbers 0-9 a second time (FIG. 3E).

[0087] As the user finishes each utterance, he presses the ‘stop’ button to terminate recording, and presses the ‘submit’ button to send the recorded utterance. After the voiceprint is successfully enrolled and stored, the user receives a confirmation (FIG. 3F).

[0088] One skilled in the art will appreciate that the use of a random signature string for authentication, coupled with the requirement that the upper confidence thresholds for both recognition of the signature string and verification of the user be exceeded provides a important liveness check, greatly minimizing the possibility that a user's voiceprint will be compromised. In particular, the requirement that the system recognizes the signature string with a high degree of confidence provides assurance that the recorded string is genuine.

[0089] Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below. 

1. A system for securing a transaction, comprising: an authentication server, wherein said server receives a request from a requestor over a network to authenticate an enrolled user of a client device, based on said user's voiceprint; and a dialog-based signature collection component adapted to present said user a random signature string and record said signature string as the user speaks it, said authentication server comprising: a recognizer adapted to recognize the recorded signature string; and a voiceprint authenticator adapted to compare said recorded signature string with a stored voiceprint of said user; wherein said user is authenticated or rejected based on result of said comparison.
 2. The system of claim 1, wherein said requestor comprises a server running a business application.
 3. The system of claim 1, wherein said requestor comprises a telephony server.
 4. The system of claim 1, wherein said requestor communicates with said server over either a data network or a voice network.
 5. The system of claim 1, wherein said client device communicates with said server over either a data network or a voice network.
 6. The system of claim 1, wherein said transaction comprises a business transaction
 7. The system of claim 1, wherein authentication is requested by signaling said authentication server an identifier, network address and, optionally, a device signature associated with said user.
 8. The system of claim 1, wherein said signature collection component comprises an interactive signature collection applet instantiated on said client device.
 9. The system of claim 8, wherein said signature collection applet is adapted to: present the user a randomly generated signature string sent from said server; prompt the user to speak the randomly generated signature string; record the said spoken signature string as an audio file, using device-specific recording objects; gather device signature configuration by reading configuration of said client device; and send said audio file and said device configuration to said authentication server.
 10. The system of claim 8, wherein said signature collection applet is adapted to report an authentication result to the user.
 11. The system of claim 8, wherein said signature collection applet is one of: pre-installed on said client device; and served up from said authentication server.
 12. The system of claim 8, wherein said signature collection applet is software and device-specific.
 13. The system of claim 8, wherein said client device includes: a software environment capable of running said signature collection applet; sufficient memory to run said applet; audio recording capabilities; readable device configuration data; and capability to send said signature string and said device configuration data.
 14. The system of claim 8, wherein said client device comprises any of: a personal computer; a WAP (wireless access protocol) telephone; a PDA (personal digital assistant); and a conventional telephone.
 15. The system of claim 1, wherein said authentication server further comprises: a dispatcher; at least one authentication client; an enrollment client; and a voiceprint server.
 16. The system of claim 15, wherein said dispatcher comprises; a load balancer, said load balancer adapted to receive authentication requests and direct said requests to available authentication clients; a logger, said logger adapted to log system load data; and a watcher, said watcher adapted to: start and shut down authentication clients in response to system demand; terminate unresponsive authentication clients; restart authentication clients that terminate abnormally.
 17. The system of claim 15, wherein said authentication client comprises: a transaction manager; a logger; a random signature generator; an applet launcher; an authentication requester; and a dialog manager.
 18. The system of claim 17, wherein said transaction manager is adapted to: receive an authentication request from said dispatcher; respond to a progress query from a requestor; and return an authentication result to a requestor.
 19. The system of claim 17, wherein said logger is adapted to: log authentication transaction data.
 20. The system of claim 17, wherein said random signature generator is adapted to: generate random signatures for use by signature collection applets.
 21. The system of claim 17, wherein said authentication requestor is adapted to: pass an audio file to said voiceprint server along with identifier of associated user; and identify best acoustic model for recognition and verification based on a client device signature.
 22. The system of claim 17, wherein said dialog manager is adapted to: supply dialog box content to applets; evaluate recognition and verification results as compared to configured thresholds; determine authentication result and potential need for retries; and interact with other clients to manage data and decision flow.
 23. The system of claim 17, wherein said enrollment client comprises: an enrollment manager; a logger; an identity manager; an applet launcher; an enrollment requestor; and a dialog manager
 24. The system of claim 23, wherein said enrollment manager is adapted to: receive enrollment request and device signature from a user; manage enrollment dialog with a user; and confirm completion of enrollment process.
 25. The system of claim 23, wherein said logger is adapted to: log enrollment transaction data.
 26. The system of claim 23, wherein said identity manager is adapted to: manage user-specific data necessary to confirm identity of a user during enrollment process.
 27. The system of claim 23, wherein said applet launcher is adapted to: serve up a device appropriate enrollment applet to a client device based on device signature and network address; receive signature files from said applet; and send enrollment result to said applet for display.
 28. The system of claim 23, wherein said enrollment requestor is adapted to: pass an audio file to said voiceprint server along with user identity information requesting recognition and verification results; and use device signature to identify best acoustic models for recognition and verification.
 29. The system of claim 28, wherein said dialog manager is adapted to: supply dialog box content to applets; evaluate recognition and verification results as compared to configured thresholds; determine authentication result and potential need for retries; interact with other clients to manage data and decision flow; and store a voiceprint in a repository.
 30. The system of claim 15, wherein said recognizer comprises at least one computer readable speech recognition program, wherein said speech recognition program recognizes said recorded signature string.
 31. The system of claim 30, wherein said voiceprint authenticator comprises at least one computer-readable program for voiceprint authentication.
 32. The system of claim 31, wherein said voiceprint server comprises: means for receiving files from said authentication client for recognition and verification; a software interface that integrates with API's to said speech recognition and voiceprint authentication programs to pass audio files and select appropriate grammars and acoustic models and to receive recognition and verification results; and a voiceprint manager for managing storage and retrieval of voiceprints from a depository.
 33. The system of claim 32, wherein said server computes confidence values for recognition and authentication, wherein minimum and maximum thresholds are set for each confidence value.
 34. The system of claim 33, wherein: if both confidence values exceed corresponding maximum thresholds, the user is authenticated; if both confidence levels fall below corresponding minimum thresholds, the user is rejected as an imposter; and if one or both confidence levels fall between thresholds, the user is prompted to re-record the signature string.
 35. The system of claim 1, further comprising means for: secure transmission among said requestor, said authentication server and said client.
 36. A method for securing a transaction, comprising: receiving a request over a network at an authentication server from a requestor to authenticate an enrolled user of a client device, based on said user's voiceprint; instantiating a dialog-based signature collection component on said client device; presenting a random signature string and recording said signature string as the user speaks it, recognizing said recorded signature string by a recognizer at said authentication server; comparing said recorded signature string with a stored voiceprint of said user by a voiceprint authenticator at said authentication server; and authenticating or rejecting said user based on an authentication result.
 37. The method of claim 36, wherein said requestor comprises a server running a business application.
 38. The method of claim 36, wherein said requestor comprises a telephony server.
 39. The method of claim 36, wherein said requestor communicates with said server over either a data network or a voice network.
 40. The method of claim 36, wherein said client device communicates with said server over either a data network or a voice network.
 41. The method of claim 36, wherein said transaction comprises a business transaction.
 42. The method of claim 36, wherein authentication is requested by signaling said authentication server an identifier, network address and optionally, a device signature associated with said user.
 43. The method of claim 36, wherein said signature collection component comprises an interactive signature collection applet.
 44. The method of claim 43, wherein the step of presenting and recording comprises the steps of: presenting the user a randomly generated signature string sent from said server; prompting the user to speak the randomly generated signature string; recording the spoken signature string as an audio file, using device-specific recording objects; gathering a device signature by reading configuration of said client device; and sending said audio file and said device configuration to said authentication server.
 45. The method of claim 43, further comprising the step of reporting the authentication result to the user through the signature collection applet.
 46. The method of claim 43, wherein said signature collection applet is one of: pre-installed on said client device; and served up from said authentication server.
 47. The system of claim 43, wherein said signature collection applet is software and device-specific.
 48. The system of claim 43, wherein said client device comprises any of: a personal computer; a WAP (wireless access protocol) telephone; and a PDA (personal digital assistant; and a conventional telephone.
 49. The method of claim 36, further comprising the step of: on said authentication server, providing any of: a dispatcher; at least one authentication client; an enrollment client; and voiceprint server.
 50. The method of claim 49, said step of providing a dispatcher comprising the steps of: receiving an authentication request at said dispatcher; and directing said request to an available authentication clients.
 51. The method of claim 49, said step of providing a dispatcher comprising the steps of: logging system load data; starting and shutting down authentication clients in response to system demand; terminating unresponsive authentication clients; and restarting authentication clients that terminate abnormally.
 52. The method of claim 49, said step of providing an authentication client comprising the steps of: receiving an authentication request from said dispatcher; responding to a progress query from a requestor; and returning an authentication result to a requestor.
 53. The method of claim 49, said step of providing an authentication client comprising the step of: logging authentication transaction data.
 54. The method of claim 49, said step of providing an authentication client comprising the step of: generating random signatures for use by signature collection applets.
 55. The method of claim 49, said step of providing an authentication client comprising the steps of: passing an audio file to said voiceprint server along with identifier of associated user; and identifying best acoustic model for recognition and verification based on a client device signature.
 56. The method of claim 49, said step of providing an authentication client comprising the steps of: supplying dialog box content to signature collection applets; evaluating recognition and verification results as compared to configured thresholds; determining authentication result and potential need for retries; and interacting with other clients to manage data and decision flow.
 57. The method of claim 49, said step of providing an enrollment client comprising the steps of: receiving enrollment request and device signature from a user; managing enrollment dialog with a user; and confirming completion of enrollment process.
 58. The method of claim 49, said step of providing an enrollment client comprising the step of: logging enrollment transaction data.
 59. The method of claim 49, said step of providing an enrollment client comprising the step of: managing user-specific data necessary to confirm identity of a user during enrollment process.
 60. The method of claim 49, said step of providing an enrollment client comprising the steps of: serving up a device appropriate enrollment applet to a client device based on device signature and network address; receiving signature files from said applet; and sending enrollment result to said applet for display.
 61. The method of claim 49, said step of providing an enrollment client comprising the steps of: passing an audio file to said voiceprint server along with user identity information requesting recognition and verification results; and using device signature to identify best acoustic models for recognition and verification.
 62. The method of claim 49, said step of providing an enrollment client comprising the steps of: supplying dialog box content to applets; evaluating recognition and verification results as compared to configured thresholds; determining authentication result and potential need for retries; interacting with other clients to manage data and decision flow; and storing a voiceprint in a repository.
 63. The method of claim 49, said recognizer comprising at least one computer readable speech recognition program.
 64. The method of claim 63, wherein said voiceprint authenticator comprises at least one computer-readable program for voiceprint authentication.
 65. The method of claim 64, the step of providing a voiceprint server comprising the steps of: receiving files from said authentication client for recognition and verification; providing a software interface that integrates with API's to said speech recognition and voiceprint authentication programs to pass audio files and select appropriate grammars and acoustic models and to receive recognition and verification results; and providing a voiceprint manager for managing storage and retrieval of voiceprints from a depository.
 66. The method of claim 65, further comprising the step of: computing confidence values for recognition and authentication, wherein minimum and maximum thresholds are set for each confidence value.
 67. The method of claim 66, further comprising one of the steps of: if both confidence values exceed corresponding maximum thresholds, authenticating the user; if both confidence levels fall below corresponding minimum thresholds, rejecting the user as an imposter; and if one or both confidence levels fall between thresholds, prompting the user to re-record the signature string.
 68. The method of claim 36, further comprising the step of: providing a secure transmission environment among said requestor, said authentication server and said client. 